1. Field of the Invention
The invention relates generally to systems, devices, and methods for monitoring a patient's respiratory system and health, including capnographers and other devices that deliver oxygen to a patient.
2. Description of the Related Art
Capnographers have been widely used for measuring concentration of carbon dioxide in a patient's exhaled breath and monitoring respiratory rate. The amount of carbon dioxide in a person's breath can indicate the overall efficiency of the cardio-pulmonary system and quality of breathing. For example, the concentration of carbon dioxide can indicate shallow breathing and poor oxygen intake. Thus, capnographers are used in hospitals and other medical institutions for monitoring the condition of a patient's respiratory system, pulmonary perfusion, and metabolism, and are most often used for patients in intensive care and under anesthesia.
A capnographer generally includes cannula tubes that conduct a patient's exhaled breath from the nasal and/or oral cavity to a collection tube that further transfers the exhaled breath to sensors. The sensors measure the concentration of carbon dioxide in the breath, and are generally located some distance away from the cannula tubes.
Capnographers are typically expensive, relatively large, and consume a large amount of power. Thus, their use is generally limited to hospitals and other controlled environments. Accordingly, there is a need for compact, inexpensive respiratory monitoring devices than can be used in and outside of hospitals to provide valuable respiratory information to doctors, nurses, paramedics, and other health care providers.